Astronomers have identified Zeta
Tucanae as a prime target for the Terrestrial
Planet Finder (TPF),
now planned for launch between
2014 and 2020.

The Star

Zeta Tucanae is a yellowish main sequence dwarf of spectral and
luminosity type F8-G0 V, with about 98 percent of Sol's mass,
1.1 times its diameter, and 1.3 times its luminosity. The star may
be only 44 to 79 percent as enriched as Sol with elements heavier than
hydrogen ("metallicity"), based on its abundance of iron
(Cayrel
de Strobel et al, 1991, page 4).
Useful star catalogue numbers for the star include: Zet Tuc, HR 77,
Gl 17, AC+48 1595, Hip 1599, HD 1581, CP(D)-65 13, SAO 248163, FK5 10,
LHS 5, LTT 167, LPM 16, and LFT 36.

Zeta Tucanae B?

Spectroscopic analysis suggests that Zeta Tucanae may have an unseen
companion.

Hunt for Substellar Companions

A radial velocity study failed to detect a brown dwarf sized companion
(with 20 to 80 times the mass of Jupiter) within 10 AUs of Zeta Tucanae
(Murdoch
et al, 1993).
The orbit of an Earth-like planet (with liquid
water) around this star would be centered around 1.14 AU -- somewhat
outside the orbital distance of Earth in the Solar System -- with an
orbital period of about one and a quarter of an Earth year.
Astronomers are hoping to use NASA's
Terrestrial
Planet Finder (TPF) and the ESA's
Darwin
planned groups of observatories to search for a rocky inner planet in the
so-called
"habitable
zone" (HZ) around Zeta Tucanae. As currently planned,
the TPF will include two complementary observatory groups:
a visible-light coronagraph to launch around 2014; and a
"formation-flying" infrared interferometer to launch before
2020, while Darwin will launch a flotilla of three
mid-infrared telescopes and a fourth communications hub
beginning in 2015.

Closest Neighbors

The following star systems are located within 10
light-years of Zeta Tucanae.

Tucana is a small constellation located around the South Pole.
For more information about the stars and objects in this constellation
and an illustration,
go to Christine Kronberg's
Tucana.
For another illustration, see David Haworth's
Tucana.

For more information about stars including spectral and luminosity
class codes, go to ChView's webpage on
The Stars of
the Milky Way.